WO1991004822A1

WO1991004822A1 - Wire guide assembly of electric discharge machine

Info

Publication number: WO1991004822A1
Application number: PCT/JP1990/001131
Authority: WO
Inventors: Toshiyuki Aso; Tomonobu Sakuragawa; Izumi Higashi
Original assignee: Fanuc Ltd
Priority date: 1989-09-27
Filing date: 1990-09-04
Publication date: 1991-04-18
Also published as: JPH03111128A; EP0445295A1; KR920700829A; EP0445295A4

Abstract

A wire guide assembly of wire cutting electric discharge machine which improves precision in working while preventing variation in wire tension, however, is simple in structure. When the supply of compressed air to an air actuator (60) at the start of discharge cutting subsequent to wire connection is suspended and a plunger (62) of the actuator is energized to the side of the wire guide by a spring (63), a movable guide member (44) is pressed to a stationary guide member (43) by the tip of the plunger and a wire path (50) through which the wire (10) is loosely passed is formed between both guide members. During discharge cutting, the wire is retained in the wire path while spaced apart from both guide members with a gap (b) at a position (a) in which the wire lies nearest both guide members, whereby no slide friction is caused between the wire conveyed along the wire path and guide members. Flowing of processing fluid is expedited and no work chips stay between the wire and guide members. As a result, the wire is free of variation in tension and precision in working is increased.

Description

Specification

Wire EDM for door-to-door electrical discharge machine

Technical field

The present invention relates to a wire door assembly of an electric discharge machine, and more particularly to a wire door assembly capable of preventing fluctuations in wire tension and improving machining accuracy.

Background technology

The wire-cut electric discharge machine that generates a discharge between the wire and the work to process the work is equipped with upper and lower wire guides arranged above and below the work, and the wire transport path The wires are constrained in wire passages formed in both guides in accordance with the above, and the wires are held on the wire transport path. In addition, the electric machine has a wire automatic for inserting the wire sent out from the upper wire guide into the groove formed through the work and the wire passage of the lower wire guide. A wire connection device is provided so that, for example, at the start of electric discharge machining, wires are stretched along a wire transport path extending between the upper and lower wire guides and downstream of the lower wire guide.

The lower wire guide is typically composed of a three-point support guide having a stationary guide member and a movable guide member which can be freely moved toward and away from the stationary guide member. The movable guide member is biased toward the stationary guide member by a spring, and the wire is slidable at three points between the V-groove formed in the stationary guide member and the opposing surface of the movable guide member. I support it. On the other hand, at the time of wire connection, the movable guide member is switched by the actuator. Driving in the direction away from the stationary guide member against the spring force of the wing, the width of the wire passage defined between both guide members is increased, and the wire to the wire passage is extended. To facilitate the insertion.

However, according to the conventional wire guide described above, the wire always contacts the stationary guide member and the movable guide member during the discharge machining, so that the wire slides between the wire and both guide members. Dynamic resistance is generated, and machining waste easily accumulates in the wire guide. Then, the wire tension fluctuates with the fluctuation of the sliding resistance caused by the accumulation of the processing chips, which adversely affects the processing accuracy. Therefore, conventionally, the wire guide is periodically removed from the electric discharge machine to clean the wire guide. However, this maintenance work requires labor. It is also known that a mechanism for adjusting the spring force of the spring is provided in the air actuator to adjust the pressing force of the movable guide member applied to the coiler to compensate for the sliding resistance fluctuation. I have. However, in this case, the configurations of the wire guide and the actuator are complicated.o

Disclosure of the invention

SUMMARY OF THE INVENTION An object of the present invention is to provide a wire cutter door assembly for a wire-cut electric discharge machine capable of preventing fluctuations in wire tension and improving machining accuracy and having a simple structure. is there.

In order to achieve the above-mentioned object, a wire guide door assembly of the present invention is provided with a stationary guide member having a wire guide groove formed therein and a movable guide member that can approach and separate from the stationary guide member. To And a movable guide member having a wire guide surface facing the wire guide groove, and when the movable guide member comes into contact with the stationary guide member, the wire guide surface is formed. O Defines a wire passage for loosely inserting the wire in cooperation with the groove

As described above, according to the present invention, the wire passage for loosely penetrating the wire is provided between the wire guide surface of the movable guide member and the wire guide groove of the stationary guide member. Since the wire is defined, a gap is provided between the wire constrained in the wire guide and the movable guide member and the stationary guide member of the wire guide. It is restrained in the via passage without contact with the wire guide. As a result, during electric discharge machining, no sliding resistance is generated between the wire and the wire guide, and the wire tension does not fluctuate due to the fluctuation of the sliding resistance. Accuracy can be improved. In addition, it is not necessary to frequently clean the wire guides because the processing chips are unlikely to stay. Further, there is no need to provide a mechanism for adjusting the wire pressing force by the movable guide member, and the configuration is simple. Further, the wire assembly of the present invention can be obtained without significantly changing the specifications of the conventional three-point support wire guide.

Brief explanation of drawings

FIG. 1 is a front view showing a lower wire door assembly according to an embodiment of the present invention, with a part cut away and an upper wire door assembly.

Fig. 2 shows the longitudinal section of the lower wire door assembly in Fig. 1. Area view,

Fig. 3 is a horizontal sectional view of the lower wire guide along the line I I I-1 1 1 in Fig. 2,

Fig. 4 is a view similar to Fig. 3 showing a modification of the lower wire guide, and

Fig. 5 is a horizontal sectional view showing a conventional lower wire guide.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIG. 1 and FIG. 2, the wire-cut discharge heater includes an upper and lower wire-gear door assembly 20 for holding the wire 10 on the wire transport path. , 30. In addition, the electric discharge machine has a conventional structure for stretching the wire 10 along a wire transfer path extending between the two assemblies 20 and 30 and downstream of the assembly 30. A known automatic wire connection device (not shown), a conventionally known detection device (not shown) for detecting the completion of wire connection, and a conventionally known coolant supply device (not shown) are provided. I have. The upper diaper door assembly 20 has a pinch roller 21 that can freely move toward and away from the electrode 22, and a pair of hold ports 23 that can freely move toward and away from each other. The wire 10 sandwiched between the hole drawers 23 is sent out toward the lower wire door assembly 30, and a machining pulse from an electric discharge machining power supply (not shown) is passed through the electrode 22. Is applied to the wire 10.

Bottom wire door Assembly 30 Bottom wire 4 0 has a guide body 41 detachably attached to the housing 31 of the assembly 30 at the flange portion 41a, and the guide body 41 has the guide body 41 attached thereto. A stepped shaft hole 41b penetrates and is formed along the axis thereof. A tip guide member 42 and a stationary guide member 43 are fitted and fixed to the large diameter portion 41b 'of the shaft hole, respectively. The tip guide member 42 is made of, for example, ruby, and an inverted conical wire guide hole 42a is formed in alignment with the shaft hole 41b. The stationary guide member 43 is formed with a V-shaped wire guide groove 43a (see Fig. 3) in a horizontal cross-section in alignment with the shaft hole 41b and the wire guide hole 42a. An opening 41c is formed in a portion of the peripheral wall of the guide body 41 facing the stationary guide member 43. A movable guide member 44 composed of, for example, a leaf spring is disposed in the opening forming portion of the guide body 41, and a base end of the movable guide member 44 fixed to the guide body 41 is provided. The free end is free to approach and move away from the stationary guide member 43.

As shown in FIG. 3, the movable guide member 44 cooperates with the stationary guide member to loosely insert the wire 10 when it comes into contact with the stationary guide member 43. A wire passage 50 having a substantially triangular shape in horizontal cross section is defined. That is, the V-groove 43 a of the stationary guide member is formed by three wires whose wires 10 that loosely pass through the wire passage 50 are closest to the guide members 43, 44. At the circumferential position a, the cross section is formed such that a gap b of a predetermined distance is provided between the wire 10 and the guide members 43, 44. For example, V groove 43a is formed so as to provide a gap b of preferably 5 to 10 mm when wires 10 of 0.2 to 0.25 mm diameter are used.

Referring again to FIG. 2, the lower wire door assembly 30 is an air actuator for driving the movable guide member 44 toward and away from the stationary guide member 43. — It has 60 evenings. The actuator 60 has a plunger 62 integrally formed with a cylinder 61, a piston 62a and a spring 63, and a movable guide member 4 is provided. The plunger 62, which has a tip freely abuttable on the plunger 4, is always urged by the spring 63 toward the movable guide member side, and the piston 62 2a is also biased toward the movable guide member side. The pressurized air is supplied to the cylindrical chamber of the above to drive the brush 62 toward the movable guide member side against the spring force of the spring 63.

Hereinafter, the operation of the upper and lower wire assemblies 20 and 30 will be described.

For example, at the start of electric discharge machining, a wire 10 is stretched along a wire carrying path by an automatic wire connection device of the electric discharge machine in a known manner. At the time of this wire connection, pressurized air is supplied to the cylinder chamber of the air actuator 60 of the lower wiring assembly 30 and the plunger 62 is sprayed. It is driven in a direction away from the lower wire guide 40 by being piled by the spring force of the ring 63, and the tip of the plunger is separated from the free end of the movable guide member 44. As a result, the leaf spring The free end of the movable guide member 44 composed of the guide member 43 is separated from the opposing end face of the stationary guide member 43, and the wire passage 50 defined by the two guide members 43, 44 is formed. Is substantially expanded.

At the time of wire connection, the upper wire door assembly 20

— The wire 10 sent out from the assembler with the rotation of the drawer 23 and then passed through the machining start hole of the work (not shown) The wire guide hole 42 a of the member 42 is inserted, and then the wire passage 50 that is communicated with the wire guide hole 42 a and expanded as described above is easily passed through. The wire 10 is sent to the downstream side via the shaft hole 41 b of the guide body 41 communicating with the wire passage 50.

When the completion of the wire connection is detected in a known manner, the supply of pressurized air to the air conditioner 60 is stopped, and the plunger 62 is turned off. 3 is urged to the lower wire guide 40 side. As a result, the free end of the movable guide member 44 is pressed by the distal end of the plunger and is pressed against the opposing end surface of the stationary guide member 43, and both guide members 43, 44 Thus, a wire passage 50 having a triangular cross section is defined. The wire 10 held in the wire passage 50 is arranged on the axis of the wire passage 50 under tension, and the wire 10 and both guide members 43 , 44 are confined in the wire passage 50 with a gap b of, for example, 5 to 10 / at the three wire circumferential positions a closest to each other. During wire-cutting electrical discharge machining, wire guide holes 42a, wire passages 50, shaft holes 41b, etc. As the wire 10 is conveyed, a high-pressure machining fluid is sprayed and supplied from the upper and lower wire assemblies 20 and 30 to the space in a known manner. Accordingly, the working fluid fills the inside of the wire passage 50 and the like. Normally, a uniform working fluid pressure is applied to the wire 10 in the wire radial direction, and the wire 10 is separated from the stationary guide member 43 and the movable guide member 44 by a gap b. It is held on the axis of the shaft 50. A film-like working fluid layer is formed in the gap b, and the deviation of the wire 10 from the axis of the wire passage is prevented. In this way, since the wire 10 is held in a non-contact state with the guide members 43, 44, the wire 10 is moved to the elements 43,, 44 'corresponding to the both guide members. Therefore, unlike the conventional wire guide supported at three points a, the sliding resistance between the wire 10 conveyed along the wire conveyance path and the guide members 43, 44 is obtained. Does not occur.

In addition, unlike the conventional wire guide in which the sliding resistance and the wire tension fluctuate due to the accumulation of the processing chips in the wire guide, the wire 10 is connected to the guide member 43. In the present embodiment, in which the flow of the machining fluid is promoted by maintaining the non-contact state from the wires 10 and 44, there is no accumulation of machining chips between the wire 10 and the guide members 43 and 44. Wire tension fluctuations and reduction in processing accuracy due to accumulation of processing waste do not occur. In addition, the wire applies the spring force applied to the wire 10 via the movable guide member 44. With the conventional wire guide that is adjusted so that it contacts the guide members 4 3 ′ and 4 4 at three points, the pressing force applied to the wire when the spring force fluctuates due to the effect of the machining fluid And the contact resistance between the wire and the two guide members, that is, the wire tension, changes. On the other hand, in this embodiment, instead of pressing the wire 10 via the movable guide member 44, the movable guide member 44 is pressed against the stationary guide member 43. In the example, the spring force of the spring 63 can be set to a large value that is not affected by the machining fluid. Therefore, the wire tension does not fluctuate due to the machining fluid, and machining accuracy is improved. improves.

The present invention is not limited to the above embodiments, and can be variously modified.

For example, in the above embodiment, the V-shaped groove 43a was formed in the stationary guide member 43, but as shown in Fig. 4, a U-shaped wire guide groove 43a 'in a horizontal sectional view was formed. It is possible.

Claims

The scope of the claims

A stationary guide member having a wire guide groove formed therein, and a wire guide surface which is disposed so as to be able to approach and separate from the stationary guide member and faces the wire guide groove. A movable guide member, and when the movable guide member contacts the stationary guide member, the wire guide surface cooperates with the wire guide groove to loosely insert the wire. Wire assembly that defines the wire passage ₀

2. The stationary guide member is provided between the wire and the guide members at the closest position between the wire and the guide members that pass through the wire passage. 2. The wire-gauge door assembly according to claim 1, wherein the wire-gauge door assembly is formed in a horizontal cross-sectional shape so as to provide a gap of a predetermined distance according to a diameter of the wire.

3. The wire guide door assembly according to claim 1, further comprising drive means for driving the movable guide member in a direction approaching and moving away from the stationary guide member.